Incest was not a taboo before civilisation

mercedo wrote today at 1:45 AM

Incest was not a taboo before civilisation - this is a hypothesis specifically viewed from economic standpoint. I believe that we had had such a state in stages of human development, though, of course I have no way to confirm.
Aside from that argument, incest has been a taboo at least after civilisation. Simply because it is the act that brings about disorder to the smallest unit of the society. Two people meet and marry, have kids. In this smallest unit only one sexual relation is allowed. Family is the place where children learn how to socialise other than sexual love. Children need to seek for their mate other than the member of their family. That is how to adjust in society apart from their family.
What was a society like before the dawn of civilisation - more than 10000 years ago allows us a lot of assumptions. Assuming they had kept on steady population and lived in a limited area, cave or something, I still think incest was not a taboo those days.